Sefo made the announcement at Friday’s WSOF 3 event. WSOF 4, meanwhile, takes place Aug. 10 at Citizens Business Bank Arena in Ontario, Calif. The main card airs on NBC Sports Network.

Sefo previously said he expected to compete on the card, though an opponent wasn’t revealed at the time. Sefo, a 2000 K-1 World Grand Prix 2000 runner-up with a 56-21-1 pro kickboxing record, fights MMA for the first time in more than two years. After an MMA victory in 2005 and one again in 2009, he suffered a submission loss to Valentijn Overeem at a Strikeforce event in 2011.

Facing the 42-year-old bossman is Huckaba, a onetime Bellator fighter and regional-circuit vet who’s won three straight fights and nine of his past 10 (seven of those nine wins have come via knockout). The 39-year-old California-based fighter was scheduled to debut at this weekend’s event against Rolles Gracie, but the Brazilian was forced off the card with an injury.

Newell, meanwhile, makes his promotional debut following a run with XFC. After splitting with the promotion with the goal of facing UFC-caliber competition, he signed a multi-fight deal with WSOF. Despite being born with just one fully developed arm, Newell has excelled with eight stoppages in nine career wins. Most recently, he submitted Bellator vet Eric Reynolds (16-5 at the time).